Reservoir and excess pressures predict cardiovascular events in high-risk patients

Background

Analysis of the arterial pressure curve plays an increasing role in cardiovascular risk stratification. Measures of wave reflection and aortic stiffness have been identified as independent predictors of risk. Their determination is usually based on wave propagation models of the circulation. Another modeling approach relies on modified Windkessel models, where pressure curves can be divided into reservoir and excess pressure. Little is known of their prognostic value.

Methods and results

The aim of this study is to evaluate the predictive value of parameters gained from reservoir theory applied to aortic pressure curves in a cohort of high-risk patients. Furthermore the relation of these parameters to those from wave separation analysis is investigated.Central pressure curves from 674 patients with preserved ejection fraction, measured by radial tonometry and a validated transfer function, were analyzed. A high correlation between the amplitudes of backward traveling pressure waves and reservoir pressures was found (R = 0.97). Various parameters calculated from the reservoir and excess pressure waveforms predicted cardiovascular events in univariate Cox proportional hazards modeling. In a multivariate model including several other risk factors such as brachial blood pressure, the amplitude of reservoir pressure remained a significant predictor (HR = 1.37 per SD, p = 0.016).

Conclusions

Based on very different models, parameters from reservoir theory and wave separation analysis are closely related and can predict cardiovascular events to a similar extent. Although Windkessel models cannot describe all of the physiological properties of the arterial system, they can be useful to analyze its behavior and to predict cardiovascular events.     

High resolution ultrasound in posterior interosseous nerve syndrome

Introduction: Posterior interosseous nerve (PIN) syndrome is a rare compression neuropathy of the PIN in the region of the supinator muscle, most common by the arcade of Frohse. We aimed to specify ultrasonographic findings in patients with PIN syndrome in comparison to healthy volunteers. Methods: Ultrasound images and clinical data of 13 patients with PIN syndrome confirmed by neurological examination and electrophysiological testing were evaluated retrospectively. Anteroposterior nerve diameters measured at the arcade of Frohse were compared with those of 20 healthy volunteers. The echotexture and the presence of a caliber change of the PIN were additionally assessed. Results: Enlargement of the PIN was seen in all patients with PIN syndrome, but not in volunteers (statistically significant difference in mean diameter P < 0.05). Furthermore, edema and caliber change of the PIN were present in all patients. Conclusions: High‐resolution ultrasound allows for differentiation between patients with PIN syndrome and healthy volunteers. Muscle Nerve 49 : 35–39, 2014     

Biomechanical Evaluation of Platform Switching: Different Mismatch Sizes,Connection Types,and Implant Protocols

Background: It is not yet well understood to what extent different implant–abutment mismatch sizes and implant–abutment connection types may influence the peri‐implant biomechanical environment of implants in different clinical situations. Methods: Computed tomography–based finite element models comprising a maxillary central incisor socket and 4.5 × 13 mm outer‐diameter implants with external and internal hex connection types were constructed. The abutments were designed with diameters of 3.5 mm (platform switching [PS] with 1 mm of diametral mismatch [PS ? 1]), 4.0 mm (PS with 0.5 mm of diametral mismatch [PS ? 0.5]), and 4.5 mm (conventional matching implant–abutment design [CD]). Analysis of variance at the 95% confidence interval was used to evaluate peak equivalent strain (EQV strain) in the bone, bone volume affected by a strain >4,000 με (EQV strain >4,000 με), the peak von Mises stress (EQV stress) in abutment screw, and the bone–implant relative displacement. Results: Similar bone strain levels (EQV strain and EQV strain >4,000 με) were encountered in PS ? 1, PS ? 0.5, and CD models for immediately placed implants, independent of the connection type. For immediately loaded implants, slightly smaller peak EQV strain and EQV strain >4,000 με were found for PS ? 1. However, for both connection types in osseointegrated models, the higher the mismatch size, the lesser the amount of strain found. Conclusions: The increase in mismatch size of PS configuration results in a significant decrease of strain levels in bone for osseointegrated implants, principally for external hex connections. No significant effect of PS could be noted in immediately placed implants.     

Impact of COMT genotype on serotonin-1A receptor binding investigated with PET

Alterations of the inhibitory serotonin-1A receptor (5-HT_1A) constitute a solid finding in neuropsychiatric research, particularly in the field of mood and anxiety disorders. Manifold factors influencing the density of this receptor have been identified, e.g., steroid hormones, sunlight exposure and genetic variants of serotonin-related genes. Given the close interactions between serotonergic and dopaminergic neurotransmission, we investigated whether a common single-nucleotide-polymorphism of the catechol-O-methyltransferase (COMT) gene (VAL158MET or rs4680) coding for a key enzyme of the dopamine network that is associated with the pathogenesis of mood disorders and antidepressant treatment response, directly affects 5-HT_1A receptor binding potential. Fifty-two healthy individuals (38 female, mean age ± standard deviation = 40.48 ± 14.87) were measured via positron emission tomography using the radioligand [carbonyl-¹¹C]WAY-100635. Genotyping for rs4680 was performed using DNA isolated from whole blood with the MassARRAY platform of the software SEQUENOM^®. Whole brain voxel-wise ANOVA resulted in a main effect of genotype on 5-HT_1A binding. Compared to A carriers (AA + AG) of rs4680, homozygote G subjects showed higher 5-HT_1A binding potential in the posterior cingulate cortex (F _(2,49) = 17.7, p = 0.05, FWE corrected), the orbitofrontal cortex, the anterior cingulate cortex, the insula, the amygdala and the hippocampus (voxel-level: p < 0.01 uncorrected, t > 2.4; cluster-level: p < 0.05 FWE corrected). In light of the frequently reported alterations of 5-HT_1A binding in anxiety and mood disorders, this study proposes a potential implication of the COMT genotype, more specifically the VAL158MET polymorphism, via modulation of the serotonergic neurotransmission.     

Biochemical analysis of the articular disc of the temporomandibular joint with magnetic resonance T2 mapping: a feasibility study

Objectives

Symptoms of temporomandibular joint (TMJ) dysfunction can seriously compromise patients' quality of life. The aim of our study was to use magnetic resonance imaging (MRI) T2 mapping of the articular disc to determine whether T2 mapping of the TMJ disc is feasible in routine clinical imaging and to assess the normal T2 relaxation time distribution within the TMJ.

Methods

Included were ten asymptomatic volunteers without pain, any mouth-opening limitations, or any clicking phenomena. MR imaging was performed on a 3-T MR scanner using a flexible, dedicated, eight-channel multielement coil. T2 mapping was performed in the oblique sagittal plane. The regions of interest (ROIs) for the T2 relaxation time maps of the disc were selected manually.

Results

The mean values for ROIs ranged between 22.4 and 28.8 ms, and the mean for all ROIs was 26.0?±?5.0 ms. Intraclass correlation (ICC) for interobserver variability was 0.698, and ICC for intraobserver variability was 0.861. There was no statistically significant difference between raters (p?=?0.091) or sides (p?=?0.810).

Conclusion

The T2 mapping technique enables ultrastructural analysis of the composition of TMJ disc. This biochemical technique is feasible in vivo, as shown in our study, when a high-field (3 T) MR and a dedicated TMJ coil are used.

Clinical relevance

T2 mapping as a biochemical technique, together with morphological MRI, may help to gain more insights into the physiology and into the pathophysiology of the articular disc in the TMJ noninvasively and in vivo.     

Concomitant overexpression of the EGFR and erbB-2 genes in renal cell carcinoma (RCC) is correlated with dedifferentiation and metastasis

Gene amplification or structural alteration of different erbB genes exerts a transforming effect in a variety of human neoplasms. Overexpression of the EGF receptor is associated with tumor initiation and progression of renal cell carcinoma (RCC). However, the role of erbB-2 in these processes remains unknown. We investigated 34 renal cell carcinomas for gene amplification and expression of the EGFR and erbB-2 genes at the mRNA and protein level and their relationship to pathological and clinical parameters. No amplification of both genes has been observed. However, high expression of the EGF receptor protein and p185erbB2 was frequent in RCC and statistically significantly related to higher tumor grades. We could demonstrate a close correlation of p185erbB2 overexpression with high EGF receptor levels. Co-overexpression of both receptor types was significantly associated with metastatic disease. Our results suggest a synergistic involvement of both EGF receptor and p185erbB2 in the progression of RCC. © 1996 Wiley-Liss, Inc.     

Central venous catheter infection by Aspergillus fumigatus in a patient with B-type non-Hodgkin lymphoma

Invasive Aspergillus infection is still a major problem in immunocompromised patients. A central venous catheter infection by Aspergillus fumigatus, however, has not yet been reported. We describe the case of a 10-year-old female patient with B-type non-Hodgkin lymphoma treated according to the German chemotherapy protocol NHI-BFM 90. Isolation of Aspergillus fumigatus from the blood was the first hint of invasive aspergillosis. A central venous catheter associated infection was suggested, since Aspergillus was also isolated from the thrombotic tip of the removed catheter. Secondary pulmonary aspergillosis was documented radiologically. The patient was treated successfully by Amphothericin B and Itraconazol and explantation of the central venous catheter under conditions of complete hematopoietic regeneration of the bone marrow with omission of the final chemotherapeutic cycle. © 1996 Wiley-Liss, Inc.     

Many-Scale Investigations of the Deformation Behavior of Polycrystalline Composites: I—Machine Learning Applied for Image Segmentation

Our work investigates the polycrystalline composite deformation behavior through multiscale simulations with experimental data at hand. Since deformation mechanisms on the micro-level link the ones on the macro-level and the nanoscale, it is preferable to perform micromechanical finite element simulations based on real microstructures. The image segmentation is a necessary step for the meshing. Our 2D EBSD images contain at least a few hundred grains. Machine learning (ML) was adopted to automatically identify subregions, i.e., individual grains, to improve local feature extraction efficiency and accuracy. Denoising in preprocessing and postprocessing before and after ML, respectively, is beneficial in high quality feature identification. The ML algorithms used were self-developed with the usage of inherent code packages (Python). The performances of the three supervised ML models—decision tree, random forest, and support vector machine—are compared herein; the latter two achieved accuracies of up to 99.8%. Calculations took about 0.5 h from the original input dataset (EBSD image) to the final output (segmented image) running on a personal computer (CPU: 3.6 GHz). For a realizable manual pixel sortation, the original image was firstly scaled from the initial resolution 10802 pixels down to 3002. After ML, some manual work was necessary due to the remaining noises to achieve the final image status ready for meshing. The ML process, including this manual work time, improved efficiency by a factor of about 24 compared to a purely manual process. Simultaneously, ML minimized the geometrical deviation between the identified and original features, since it used the original resolution. For serial work, the time efficiency would be enhanced multiplicatively.     

Sjögren-Lupus erythematodesÜberlappungssyndrom

Zusammenfassung Patienten mit ph?notypischer Sj?gren-Syndrom (SS)-Lupus erythematodes(LE)-überlappung stellen eine immungenetisch, serologisch und klinisch einheitliche Krankheitsgruppe dar mit polyzyklisch-anul?ren, erythematosquam?sen Hautl?sionen, zirkulierenden SSA(Ro)-Antik?rpern und hoher Pr?valenz des immungenetischen Ph?notyps HLA-DR3. Die Sicca-Symptomatologie des SS kann der LE-Symptomatik zeitlich folgen oder vorangehen. Neben Hautver?nderungen wie beim subakuten kutanen LE (SCLE) kommt es zu vaskulitischen, purpuriformen und Sweet-Syndrom-artigen Hautl?sionen. Die ?lteren, vornehmlich weiblichen Patienten zeigen ein erh?htes Risiko pulmonaler und neurologischer Komplikationen. Demgegenüber kommt es selten zu einer Nierenbeteiligung. Eine 81j?hrige, anti-SSA(Ro)-, HLA-DR3-positive Frau mit 30j?hriger Anamnese eines kutanen LE wird vorgestellt, bei der erst Jahre sp?ter neben den Hautver?nderungen eines SCLE eine Sicca-Symptomatik, vaskulitische und Sweet-Syndrom-artige Hautver?nderungen auftraten. Wenngleich diskutiert werden kann, ob es sich bei der ph?notypischen SS-LE-überlappung um ein eigenst?ndiges Krankheitsbild oder um einen LE mit sekund?rem SS bzw. ein prim?res SS mit Hautmanifestationen handelt, scheint das SS-LE-überlappungssyndrom hinreichend gut charakterisiert, um es als eine Krankheitsentit?t mit eigenen Implikationen für die Therapie und Prognose anzuerkennen. Die Stellung des SS/LE-überlappungssyndroms im Spektrum der anti-SSA(Ro)-, HLA-DR3-positiven Erkrankungen, und die enge immunologische Verwandtschaft zum SS und zum anti-SSA(Ro)-positiven LE werden diskutiert. Eingegangen am 5. April 1994 Angenommen am 24. August 1994